\version "2.15.39"

sopranoI = \relative c'' {
  \set melismaBusyProperties = #'()
  \dynamicUp
  c\p ( d e\mf f )
}

sopranoIWords = \lyricmode {
  A b c d
}

sopranoII = \relative c'' {
  \set melismaBusyProperties = #'()
  \dynamicUp
  c\p b ( a\mf g )
}

sopranoIIWords = \lyricmode {
  A b c d
}

sopranoIII = \relative c'' {
  \set melismaBusyProperties = #'()
  \dynamicUp
  c\p ( g ) f\mf ( e )
}

sopranoIIIWords = \lyricmode {
  D c b a
}

\score {
  \new ChoirStaff <<
    \new Staff <<
      \set Staff.instrumentName = "Soprano I"
      \new Voice = "Soprano I" \sopranoI
      \lyricsto "Soprano I" \new Lyrics \sopranoIWords
    >>

    \new Staff <<
      \set Staff.instrumentName = "Soprano II"
      \new Voice = "Soprano II" \sopranoII
      \lyricsto "Soprano II" \new Lyrics \sopranoIIWords
    >>

    \new Staff <<
      \set Staff.instrumentName = "Soprano III"
      \new Voice = "Soprano III" \sopranoIII
      \lyricsto "Soprano II" \new Lyrics \sopranoIIIWords
    >>

    \new Staff \with { printPartCombineTexts = ##f } {
      \set Staff.instrumentName = \markup \center-column {
        "Sopranos"
        "I - II"
      }
      \partcombine
      \sopranoI
      \sopranoII
    }
  >>
}